Earth Science: Mammals – Elephants and Sea Cows
Elephants and manatees are closely related to each other. The elephant is the largest mammal living on land, while sea cows (manatees and dugongs) have adapted themselves to living only in water.
Three species of elephant exist today: the African elephant, the forest elephant, and the Asian elephant. They live in grasslands, savannas, mountainous areas, and forests. An elephant’s trunk is an elongated nose, with the nostrils located high up on the skull.
Extremely strong trunk muscles allow it to be used to dig watering holes, tear bark off trees, intimidate enemies, and for defense. Because elephants’ skin is sensitive and very thin in some places, especially near the stomach and behind the ears, the animals bathe in water and mud to cool and care for their skin.
Since they do not possess sweat glands, excess heat is released through their large ears. Their pillar legs end in vestigial hooves with tissue padding. When walking, they make very little noise, despite their size. Their heavy tusks are transformed upper incisors that can grow to up to 11.5 feet (3.5 m) long.
The legendary memory of the elephant has been partly confirmed: even 70-yearolds can find their way back to the watering holes of their youth. Sea cows (manatees and dugongs), named for their herbivorous diet, are closely related to elephants—although there are few visual similarities.
Only the short tusks of the dugong give a clue to their elephant relatives. They are fully adapted to aquatic life. Instead of fore- legs they have flippers; their hind legs have receded, and the base of their body tapers to a rounded paddle-shaped tail. The body of a mature sea cow is around 13 feet (four m) long and weighs up to 1,320 pounds (600 kg).
They swim slowly or drift in the water and can dive for up to 20 minutes. Sea cows live either alone or in small groups. A sea cow is born after a gestation period of 12 to 14 months and mothers suckle the young, only underwater. Manatees are found in the shallow waters of coastal areas and bays of tropical seas, and at the mouths of rivers.
ISSUES TO SOLVE
THE IVORY TRADE and the poaching of elephants has nearly resulted in their extinction. A ban on trade since 1989 has helped little, due to smuggling and inefficient checks.